For fine machining of surfaces of various products by grinding, polishing and the like, grinding disks are often used which are driven usually by a hand-held drive machine by means of a usually standardized drive connection in a concentrically or eccentrically rotating or alternating movement and on which at a bottom side a proper working material is arranged on a preferably planar bottom surface. In this context, the working material can be fixedly attached to the support surface of the grinding disk located at the bottom side, but it is also possible that the working material is exchangeable, for example, in the form of an abrasive sheet, in that it is releasably attached adhesively by means of an intermediate layer that is provided with an adhesive layer or a hook-and-loop fastener or is clamped at least at one clamping area.
An important part of such a grinding disk is in any case an elastically deformable pad for a more uniform pressure application of the contact surface; such pads have been conventionally produced primarily of foamed elastomeric synthetic material. Such a soft-elastic material was then stabilized usually by a top-side support plate by means of which, in case of grinding disks with extraction passages, also air guiding passages are integrated. Examples of this kind are disclosed in US 2013/0157552 A1 and in EP 2 366 498 A2.
A disadvantage of processing foamed shaped parts of elastomeric synthetic material is, on the one hand, the processing time for foaming and curing which, in particular in regard to high production output tailored to suit the market need, has a slowing effect. The difficult connection to the pad and to the support plate with regard to the extremely different material properties is also disadvantageous.
U.S. Pat. No. 7,223,165 B2 discloses in contrast thereto a grinding disk for fine machining comprising an abrasive sheet or a similar working material that is to be attached to the bottom side of a mostly closed support surface of an elastically deformable pad, wherein the pad is comprised of an injection-molded part of un-foamed elastomeric thermoplastic synthetic material with chamber structures that at least at one side are open and delimited by intermediate walls, wherein the pad on the side opposite the support surface is supported by a support plate of strong material that is connected to a drive connector. The pad is designed to be soft and yielding, as required, by an injection molding process without foaming by being shaped with chamber structures that are open at least at one side. Such an injection molding process enables much higher cycle times in manufacture. In this context, a transition to partially stiffer retaining structures can be provided by a two-component injection molding process in which the upper areas that are oppositely positioned relative to the softer support surface of the pad are made of a second harder material. This possibility is however limited to very limited material combinations and is limited with regard to the stiffening effect. It must also be accepted that the chamber structures that are open at the top side remain open and are prone to soiling. For practical use it is also disadvantageous that according to this prior art a support plate is to be provided as a flange of a drive connector which is to be secured with several screw connections to the pad. This limits the mechanical properties of the grinding disk and also requires a significant mounting expenditure.